Zeolite-based phosphate-free detergent builder composition

ABSTRACT

PCT No. PCT/EP91/01976 Sec. 371 Date Apr. 26, 1993 Sec. 102(e) Date Apr. 26, 1993 PCT Filed Oct. 17, 1991 PCT Pub. No. WO92/07928 PCT Pub. Date May 14, 1992.Phosphate-free builder combinations containing zeolite, crystalline layer silicates corresponding to formula (I) NaMSixO2x+1.yH2O, in which M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20, and polymeric polycarboxylates may be used separately as water softeners or in detergents. Their primary and secondary detergent properties are so favorable that there is little or no need to use phosphonates.

FIELD OF THE INVENTION

1. Field of the Invention

This invention relates to a phosphate-free builder combination, to aprocess for its production and to a detergent containing this buildercombination.

In practice, phosphate Substitutes in detergents include, above all,zeolite, particularly zeolite NaA, and mixtures of zeolite with alkalimetal silicates and carbonates and also polymeric polycarboxylates.Other phosphate substitutes which have been used are complexing agents,such as the salts of nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and phosphonic acids. The function of thecomplexing agents, most of which have a selective effect, is toeliminate heavy metal ions which, even in traces, have a veryunfavourable effect on the washing process (Ullmann, 1987, Vol. 8, pages351 to 354). It is known that phosphonates also counteract theprecipitation of poorly soluble calcium salts and, hence, theincrustation and discoloration of fabrics produced by poorly solublecalcium salts ("Einsatz yon Phosphonaten in flussigen Vollwaschmitteln",M. Paladini, G. Schnorbus, Seifen-Ole-Fette-Wachse, Vol. 114 (1989),pages 508 to 511). Finally, the combined use of phosphonates andcopolymers based on acrylic acid and maleic acid provides the fabricswith greater whiteness by comparison with formulations containing onlyone of these two components ("Einsatz yon Phosphonaten inHaushaltswaschmitteln mit niedrigem Phosphorgehalt (1%)", M. Paladini,G. Schnorbus, Seifen-Ole-Fette-Wachse, Vol. 115 (1988), pages 756 to760).

2. Discussion of Related Art

European patent application 291 869 describes phosphate-free buildercombinations of zeolite, aminoalkane polyphosphonate,1-hydroxyethane-1,1-diphosphonate (HEDP) and polymeric polycarboxylate,certain ratios by weight of the last three components showing asynergism in regard to the prevention of fiber incrustations.

Crystalline, layer-form sodium silicates have also been described assubstitutes or partial substitutes for phosphates and zeolites. Thus,European patent application 164 514 discloses a phosphate-free buildercombination which mainly contains crystalline layer silicatescorresponding to formula (I) NaMSi_(x) O₂₊₁._(y) H₂ O, where M is sodiumor hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to 20,preferred values for x being 2, 3 or 4. They may be used as watersofteners both separately and in detergents together with otherbuilders, such as phosphates, zeolite, other silicates, phosphonates andpolycarboxylates.

European patent applications 337 217 and 337 219 describe buildercombinations for detergents which contain crystalline layer silicatescorresponding to formula (I) above and, optionally, phosphates andpolycarboxylates, such as citrates, gluconates, NTA and/oriminodiacetates, but no zeolite.

DESCRIPTION OF THE INVENTION

The problem addressed by the present invention was further to developthe field of phosphate-builder combinations with a view to reducing thecontent of organic synthetic compounds. It has surprisingly been foundthat the combination of fine-particle zeolite, crystalline layersilicate and a certain polymeric polycarboxylate meets the stringentdemands imposed on the primary detergent effect and on the secondaryproperties, more particularly the inhibition of incrustation on fabricsand the prevention of deposits in washing machines, so effectively thatthere is virtually no need to use phosphonates and, preferably, no needat all to use phosphonates.

In a first embodiment, therefore, the present invention relates to aphosphate-free builder combination containing zeolite, polymericpolycarboxylate and crystalline layer silicate corresponding to formula(I) NaMSi_(x) O_(2x+1)._(y) H₂ O, where M is sodium or hydrogen, x is anumber of 1.9 to 4 and y is a number of 0 to 20, and optionallyphosphonates.

In another embodiment, the present invention relates to a detergentcontaining this phosphate-free builder combination of zeolite,crystalline layer silicates corresponding to formula (I) and polymericpolycarboxylates.

The zeolites are used in the typical hydrated, finely crystalline form.They contain hardly any particles larger than 30 μm in size, at least80% of the zeolites preferably consisting of particles smaller than 10μm in size. Their calcium binding power, as determined in accordancewith German patent application 24 12 837, is in the range from 100 to200 mg CaO/g. Zeolite NaA is particularly suitable, although zeolite NaXand mixtures of NaA and NaX may also be used. The builder combinationsaccording to the invention preferably contain 60 to 96% by weight and,more particularly, 65 to 85% by weight hydrated zeolite.

The crystalline layer silicates corresponding to formula (I) arepreferably those in which M is sodium and x assumes a value of 2 or 3.Particularly preferred crystalline layer silicates are both β- andδ-sodium disilicates Na₂ Si₂ O₅._(y) H₂ O. β-Sodium disilicate may beobtained, for example, by the process described in International patentapplication WO 91/08171. The builder combinations according to theinvention preferably contain the crystalline layer silicates inquantities of 2 to 25% by weight and, more preferably, in quantities of3 to 15% by weight.

Suitable polymeric polycarboxylates are polymeric carboxylic acidshaving a relative molecular weight of at least 350 in the form of theirwater-soluble salts, more particularly in the form of the sodium and/orpotassium salts, such as polyacrylates, polyhydroxyacrylates,polymethacrylates, polymaleates and, more particularly, copolymers ofacrylic acid with maleic acid or maleic anhydride, preferably those of50 to 90% acrylic acid and 50 to 10% maleic acid. The relative molecularweight of the homopolymers is generally in the range from 1,000 to100,000 while the relative molecular weight of the copolymers is in therange from 2,000 to 200,000 and preferably in the range from 50,000 to120,000, based on free acid. A particularly preferred acrylicacid/maleic acid copolymer has a relative molecular weight of 50,000 to100,000. Suitable, albeit less preferred compounds of this class arecopolymers of acrylic acid or methacrylic acid with vinyl ethers, suchas vinyl methyl ethers, vinyl esters, ethylene, propylene and styrene,in which the acid makes up at least 50%. The polymeric polycarboxylatespreferably make up 2 to 16% by weight and, more preferably, 3 to 14% byweight of the builder combinations.

Preferred builder combinations contain crystalline layer silicates andpolymeric polycarboxylates in a ratio by weight of 3:1 to 1:3.Crystalline layer silicates and polymeric polycarboxylates are used withparticular advantage in a ratio by weight of 1.5:1 to 1:2.

In one preferred embodiment, the builder combinations according to theinvention contain no phosphonates because, even without phosphonates,the builder combinations surprisingly have a synergistic effect in thewashing process in regard to the whiteness of the fabrics and improvethe stabilization of the peroxy bleach.

Surprisingly, there is also no need to use other complexing agents orpolycarboxylates, such as gluconate, EDTA, NTA, citrate oriminodiacetate.

In another preferred embodiment, the products according to the inventionadditionally contain amorphous, alkaline or neutral alkali metalsilicates, more particularly sodium and/or potassium silicates, in whichthe ratio of M₂ O to SiO₂ is from 1:1 to 1:3.5. Preferred buildercombinations contain alkali metal silicates with an Na₂ O to SiO₂ ratioof 1:2.0 to 1:3.3 and, more particularly, to 1:3.0. The quantities ofamorphous alkali metal silicate to be used are selected so that theratio by weight of crystalline layer silicate to amorphous alkali metalsilicate is between 1.5:1 and 1:2 and more particularly between 1.2:1and 1:1.7. Builder combinations in which the ratio by weight ofcrystalline layer silicate to polymeric polycarboxylate to amorphousalkali metal silicate is 1:(0.9-1.5):(1.2-1.5) are used with particularadvantage.

The detergents containing the builder combinations according to theinvention may be present in solid, liquid or paste-like form. Theycontain the builder combination preferably in quantities of 31 to 60% byweight and, more preferably, in quantities of 35 to 50% by weight.Preferred detergents contain 20 to 40% by weight and, more particularly,26 to 35% by weight finely crystalline and hydrated zeolite of the Aand/or X type, 1 to 15% by weight and, more particularly, 1.5 to 7% byweight crystalline layer silicates corresponding to formula (I), 1 to 9%by weight and, more particularly, 1.5 to 7% by weight polymericpolycarboxylates and 2 to 10% by weight and, more particularly, 2 to 8%by weight amorphous alkali metal silicates with an Na₂ O to SiO₂ ratioof 1:2.0 to 1:3.3.

In addition, the detergents may contain up to 10% by weight sodiumcarbonate. Detergents containing at most up to 5% by weight sodiumcarbonate are preferred.

The detergents contain known compounds from the group of anionic,nonionic and zwitterionic surfactants as further constituents.Sulfonates and sulfates and also soaps of preferably natural fatty acidsor fatty acid mixtures are particularly suitable as the anionicsurfactants. C₉₋₁₃ alkylbenzene sulfonates, olefin sulfonates, esters ofα-sulfofatty acids or α-sulfofatty acid disalts, for example, are usedas surfactants of the sulfonate type. Suitable surfactants of thesulfate type are the sulfuric acid monoesters of primary alcohols ofnatural or synthetic origin, i.e. of C₁₂₋₁₈ fatty alcohols or C₁₀₋₂₀oxoalcohols, and those of secondary alcohols having the same chainlength. The sulfuric acid monoesters of alcohols reacted with 1 to 6 molethylene oxide (EO) are also suitable. Suitable nonionic surfactantsare, above all, adducts of preferably 2 to 20 mol EO with 1 mol of analiphatic compound essentially containing 10 to 20 carbon atoms from thegroup consisting of alcohols, carboxylic acids, fatty amines, carboxylicacid amides and alkane sulfonamides. In addition to water-solublenonionic surfactants, however, water-insoluble or substantiallywater-insoluble polyglycol ethers containing 2 to 7 ethylene glycolether units in the molecule are important, particularly when they areused together with water-soluble nonionic or anionic surfactants. Othersuitable nonionic surfactants are alkyl polyglycosides corresponding tothe general formula R--O--(G)_(x), in which R is a primary, linear or2-methyl-branched aliphatic radical containing 8 to 22 and preferably 12to 18 carbon atoms, G is a symbol which stands for a glycose unitcontaining 5 or 6 carbon atoms and the degree of oligomerization x isbetween 1 and 10.

The total surfactant content of the detergents is between 5 and 40% byweight, preferably between 5 and 30% by weight and, more preferably,between 8 and 25% by weight.

Other constituents of the detergents, which may make up as much as 60%by weight and preferably from 5 to 50% by weight of the detergents,depending on their composition, include redeposition inhibitors, foaminhibitors, bleaches and bleach activators, optical brighteners,enzymes, fabric softeners, dyes and fragrances and also neutral salts,solvents and water.

Among the compounds yielding H₂ O₂ in water which are used as bleaches,sodium perborate tetrahydrate (NaBO₂.H₂ O.3H₂ O) and sodium perboratemonohydrate (NaBO₂.H₂ O₂) are particularly important. Other suitablebleaches are, for example, peroxycarbonate (Na₂ CO₃.1.5H₂ O₂) orperacidic salts of organic acids, such as perbenzoates or salts ofdiperdodecanedioic acid.

To obtain an improved bleaching effect where washing is carried out attemperatures of or below 60° C., bleach activators may be incorporatedin the preparations. Examples of suitable bleach activators are theN-acyl or O-acyl compounds which form organic peracids with H₂ O₂,preferably N,N'-tetraacylated diamines, such as N,N,N',N'-tetraacetylethylenediamine.

Suitable enzymes are those from the classes of proteases, lipases andamylases or mixtures thereof. The enzymes may be adsorbed on supportsand/or encapsulated in shell-forming substances to protect them againstpremature decomposition.

Suitable and preferred non-surface-active foam inhibitors areorganopolysiloxanes and mixtures thereof with microfine, optionallysilanized silica, paraffins, waxes, microcrystalline waxes and mixturesthereof with silanized silica. Mixtures of different foam inhibitors,for example mixtures of silicones and paraffins or waxes, may also beused with advantage. The foam inhibitors are preferably fixed to agranular support soluble or dispersible in water.

In one preferred embodiment, powder-form or granular detergents containfrom 10 to 20% by weight surfactants, 26 to 35% by weight zeolite NaA, 2to 5% by weight crystalline layer silicates corresponding to formula(I), in which M is sodium and x has the value 2, 2 to 5% by weightpolymeric polycarboxylates, 2 to 5% by weight amorphous alkali metalsilicates and also 15 to 30% by weight bleach and 0.1 to 1% by weightenzyme. The apparent density of the detergents is preferably between 400and 900 g/l.

Both the builder combinations according to the invention and thedetergents according to the invention may be produced by methods knownper se, for example by mixing, granulation and/or by spray-drying. Inthe case of the detergents, separately prepared builder combinations maybe used. The various builders may also be incorporated in the detergentsindividually in known manner and in any order.

The pourable powder-form or granular preparations preferably consist ofa dry homogeneous mixture of at least two powder components, of whichthe first is present in the form of spray-dried granules. The granulesmay be obtained by conventional spray-drying of a slurry containingzeolite, preferably in the form of an aqueous suspension, in admixturewith the sodium salt of the (co)polymeric acids as builders. As isusually the case, bleaches, such as perborate, are not spray-driedtogether with the constituents of the first powder component on accountof their sensitivity to heat, but are subsequently incorporated in thespray-dried product. Any amorphous alkali metal silicates present arealso preferably not spray-dried together with the zeolite-containingslurry. Similarly, the crystalline layer silicates are preferably notspray-dried, but instead are incorporated in granular form or adsorbedonto a support consisting of sulfate and/or carbonate.

EXAMPLES

Granular detergents having the composition shown below were prepared andtested. The constituents mentioned in first to sixth place and alsozeolite NaA and sodium sulfate were mixed to form an aqueous slurry andspray-dried in a test tower. The perborate, the bleach activator and thegranules were subsequently incorporated in the spray-dried product.

Testing was carried out under simulated practical conditions in domesticwashing machines. To this end, the machines were loaded with 3.5 kgnormally soiled domestic washing (bed linen, table linen, underwear) and0.5 kg test fabrics. Strips of standardized cotton fabric(Wascheforschungsanstalt Krefeld), nettle, knitted fabric (cottontricot) and terry were used as the test fabrics. Washing conditions:tapwater having a hardness of 23.d (equivalent to 230 mg CaO/l), mainwash cycle 8.0 g/l at 25° to 90° C. (heating time 60 minutes, 15 minutesat 90° C.), liquor ratio (kg washing:liter wash liquor in the main washcycle) 1:4, 5× rinsing with tapwater, spinning and drying.

The test fabrics were provided with bleachable and enzyme-degradablesoils. The use of the powder detergent containing a builder combinationaccording to the invention produced comparable to better results inregard to whiteness than the powder detergent containing a standardbuilder combination (measurement of whiteness: Zeiss reflectometer, 465nm, blanking out of the effect of the brightener).

After 50 wash cycles, the ash content of the fabric samples wasquantitatively determined. Averaged out over all the test fabrics, thepowder detergent containing the builder combination according to theinvention showed comparable to better ash contents than the standardpowder detergent.

    ______________________________________                                        Composition                                                                   ______________________________________                                        1.   7.0% by weight                                                                             sodium dodecyl benzenesulfonate                             2.   1.5% by weight                                                                             sodium C.sub.12-18 fatty acid soap                          3.   1.5% by weight                                                                             sodium tallow soap                                          4.   6.5% by weight                                                                             C.sub.12-18 fatty alcohol containing 5 EO                   5.   0.8% by weight                                                                             cellulose ether                                             6.   0.2% by weight                                                                             optical brightener                                          7.   38.5% by weight                                                                            builder combination                                         8.   26.0% by weight                                                                            sodium perborate tetrahydrate                               9.   2.0% by weight                                                                             tetraacetyl ethylenediamine (TAED)                          10.  0.5% by weight                                                                             granular enzyme                                             11.  0.2% by weight                                                                             granular silicone foam inhibitor                                 balance      sodium sulfate, water                                       ______________________________________                                    

Builder combination (in % by weight, based on the detergent as a whole)

    ______________________________________                                                          Standard                                                                             Invention                                                              C      I                                                    ______________________________________                                        Zeolite NaA, hydrated                                                                             31.0     31.0                                             Sodium silicate, amorphous                                                                        3.0      3.0                                              (Na.sub.2 O:SiO.sub.2 ═1:3.0)                                             Sokalan CP5 ®   4.0      2.5                                              (Acrylic acid/maleic acid                                                     copolymer, a commercial product                                               of BASF)                                                                      Na-SkS6 ®       --       2.0                                              (δ-sodium disilicate, a commercial                                      product of Hoechst AG)                                                        HEDP tetrasodium salt                                                                             0.5      --                                               ______________________________________                                    

Stabilization of the peroxide bleach

Washing conditions:

Tapwater, 17.d (equivalent to 170 mg CaO/l),

Main wash cycle at 25°-90° C. (heating time 60 minutes, 15 minutes at90° C.)

Liquor ratio (kg washing: 1 wash liquor in main wash cycle) 1:4

5× Rinsing with tapwater, spinning and drying,

Dosage of detergent: 140 g

The machines were again loaded with 3.5 kg normally soiled domesticwashing and 0.5 kg test fabrics. Strips of standardized cotton fabric(Waschereiforschungsanstalt Krefeld), of crease-resistant cotton fabricand of a blended fabric of polyester and crease-resistant cotton wereused as the test fabrics.

Soils: Grease/pigment soils and bleachable soils, such as red wine, tea,cocoa, blueberry

The detergents used were detergents having the above compositioncontaining builder combinations I and C. In this case, however,amorphous sodium silicates with a ratio of Na₂ O to SiO₂ of 1:2.0 (I1,C1) and 1:2.6 (I2, C2) were used.

The tests were each carried out three times. The remission values shown(measurement: see above) represent the average values of all themeasurements.

In another series of tests, 10 ppm divalent copper ions (Cu²⁺ in theform of copper sulfate) were added to the wash liquor in quantities of10 ppm. In this case, too, the remission values shown represent theaverage values of all the measurements.

The Table clearly shows that detergents I1, I2, C1 and C2 performcomparably in test series a) (detergent with no added copper). In testseries b) (detergent containing 10 ppm Cu²⁺) detergents I1 and I2according to the invention performed significantly better than C1 and C2on all soils.

                  TABLE                                                           ______________________________________                                                    % Remission for detergents containing                                         the builder combinations                                          Test series   C1     I1         C2   I2                                       ______________________________________                                        a)    Detergent   78.1   77.9     77.5 77.7                                   b)    Detergent + 54.8   64.1     55.0 69.2                                         10 ppm Cu.sup.2+                                                        ______________________________________                                    

We claim:
 1. A phosphate-free builder composition consisting essentiallyof from 60 to 96% by weight of zeolite, from 2 to 16% by weight ofpolymeric polycarboxylate, and from 2 to 25% by weight of crystallinelayer silicate corresponding to formula (I) NaMSi_(x) O_(2x+1)._(y) H₂O, wherein M is sodium or hydrogen, x is a number of 1.9 to 4 and y is anumber of 0 to
 20. 2. A phosphate-free builder composition as in claim 1wherein said crystalline layer silicate and said polymericpolycarboxylate are present in a ratio by weight of 3:1 to 1:3, M informula (I) is sodium, and x is the number 2 or
 3. 3. A phosphate-freebuilder composition as in claim 1 further containing amorphous sodiumsilicates having a ratio of Na₂ O to SiO₂ of from 1:2.0 to 1:3.3 whereinthe ratio by weight of crystalline layer silicate to said amorphoussodium silicate is from 1.5:1 to 1:2.
 4. A phosphate-free buildercomposition as in claim 1 wherein at least 80% of said zeolite has aparticle size smaller than 10 μm.
 5. A phosphate-free buildercomposition as in claim 4 wherein said zeolite is selected from thegroup consisting of zeolite NaA, zeolite NaX and mixtures thereof.
 6. Aphosphate-free builder composition as in claim 1 wherein saidcrystalline layer silicate is selected from the group consisting ofβ-sodium disilicate, δ-sodium disilicate, and mixtures thereof.
 7. Aphosphate-free builder composition as in claim 1 wherein said polymericpolycarboxylate is selected from the group consisting of polyacrylates,polyhydroxyacrylates, polymethacrylates, polymaleates, and copolymers ofacrylic acid with maleic acid or maleic anhydride.
 8. A detergentcomposition containing from 31% to 60% by weight of a phosphate-freebuilder composition consisting essentially of from 60 to 96% by weightof zeolite, from 2 to 16% by weight of polymeric polycarboxylate, andfrom 2 to 25% by weight of crystalline layer silicate corresponding toformula (I) NaMSi_(x) O_(2x+1)._(y) H₂ O, wherein M is sodium orhydrogen, x is a number of 1.9 to 4 and y is a number of 0 to
 20. 9. Adetergent composition as in claim 8 wherein said crystalline layersilicate and said polymeric polycarboxylate are present in a ratio byweight of 3:1 to 1:3, M in formula (I) is sodium, and x is the number 2or
 3. 10. A detergent composition as in claim 8 further containingamorphous sodium silicates having a ratio of Na₂ to SiO₂ of from 1:2.0to 1:3.3 wherein the ratio by weight of crystalline layer silicate tosaid amorphous sodium silicate is from 1.5:1 to 1:2.
 11. A detergentcomposition as in claim 8 wherein at least 80% of said zeolite has aparticle size smaller than 10 um.
 12. A detergent composition as inclaim 8 wherein said zeolite is selected from the group consisting ofzeolite NaA, Zeolite NaX and mixtures thereof.
 13. A detergentcomposition as in claim 8 wherein said crystalline layer silicate isselected from the group consisting of β-sodium disilicate, δ-sodiumdisilicate, and mixtures thereof.
 14. A detergent composition as inclaim 8 wherein said polymeric polycarboxylate is selected from thegroup consisting of polyacrylates, polyhydroxyacrylates,polymethacrylates, polymaleates, and copolymers of acrylic acid withmaleic acid or maleic anhydride.
 15. A phosphate-free detergentcomposition consisting essentially of from 20 to 40% by weight ofzeolite, from 1 to 15% by weight of crystalline layer silicatecorresponding to formula (I) NaMSi_(x) O_(2X+1)._(y) H₂ O wherein M issodium or hydrogen, x is a number of 1.9 to 4 and y is a number of 0 to20, from 1 to 9% by weight of polymeric polycarboxylate, and from 2 to8% by weight of amorphous alkali metal silicate having a Na₂ to SiO₂ratio of from 1:2.0 to 1:3.3.